Bleeding,hemorrhage,haemorrhage orblood loss isblood escaping from thecirculatory system from damagedblood vessels.[1] Bleeding can occurinternally, or externally either through a natural opening such as themouth,nose,ear,urethra,vagina oranus, or through a puncture in theskin.Hypovolemia is a massive decrease in blood volume, and death by excessive loss of blood is referred to asexsanguination.[2] Typically, a healthy person can endure a loss of 10–15% of the total blood volume without seriousmedical difficulties (by comparison,blood donation typically takes 8–10% of the donor's blood volume).[3] The stopping or controlling of bleeding is calledhemostasis and is an important part of bothfirst aid andsurgery.
Subarachnoid hemorrhage (SAH) implies the presence of blood within thesubarachnoid space from some pathologic process. The common medical use of the term SAH refers to the nontraumatic types of hemorrhages, usually from rupture of a berry aneurysm orarteriovenous malformation (AVM).[4] The scope of this article is limited to these nontraumatic hemorrhages.
Eyes
Subconjunctival hemorrhage — bloody eye arising from a broken blood vessel in thesclera (whites of the eyes). Often the result of strain, including sneezing, coughing, vomiting or other kind of strain
Traumatic bleeding is caused by some type of injury. There are different types ofwounds which may cause traumatic bleeding. These include:
Abrasion — Also called a graze, this is caused by transverse action of a foreign object against the skin, and usually does not penetrate below theepidermis.
Excoriation — In common with Abrasion, this is caused by mechanical destruction of the skin, although it usually has an underlying medical cause.
Hematoma — Caused by damage to a blood vessel that in turn causes blood to collect in an enclosed area.
Laceration — Irregular wound caused by blunt impact to soft tissue overlying hard tissue or tearing such as in childbirth. In some instances, this can also be used to describe an incision.
Incision — A cut into a body tissue or organ, such as by ascalpel, made during surgery.
Puncture Wound — Caused by an object that penetrated the skin and underlying layers, such as a nail, needle or knife.
Contusion — Also known as a bruise, this is a blunt trauma damaging tissue under the surface of the skin.
Crushing Injuries — Caused by a great or extreme amount of force applied over a period of time. The extent of a crushing injury may not immediately present itself.
Ballistic Trauma — Caused by a projectile weapon such as a firearm. This may include two external wounds (entry and exit) and a contiguous wound between the two.
The pattern of injury, evaluation and treatment will vary with the mechanism of the injury. Blunt trauma causes injury via a shock effect; delivering energy over an area. Wounds are often not straight and unbroken skin may hide significant injury. Penetrating trauma follows the course of the injurious device. As the energy is applied in a more focused fashion, it requires less energy to cause significant injury. Any body organ, including bone and brain, can be injured and bleed. Bleeding may not be readily apparent; internal organs such as the liver, kidney and spleen may bleed into the abdominal cavity. The only apparent signs may come with blood loss. Bleeding from a bodily orifice, such as the rectum, nose, or ears may signal internal bleeding, but cannot be relied upon. Bleeding from amedical procedure also falls into this category.[citation needed]
"Medical bleeding" denotes hemorrhage as a result of an underlying medical condition (i.e. causes of bleeding that are not directly due to trauma). Blood can escape fromblood vessels as a result of 3 basic patterns of injury:[citation needed]
The underlying scientific basis for blood clotting and hemostasis is discussed in detail in the articles,coagulation,hemostasis and related articles. The discussion here is limited to the common practical aspects of blood clot formation which manifest as bleeding.
Some medical conditions can also make patients susceptible to bleeding. These are conditions that affect the normal hemostatic (bleeding-control) functions of the body. Such conditions either are, or cause,bleeding diatheses.Hemostasis involves several components. The main components of the hemostatic system includeplatelets and thecoagulation system.
Platelets are small blood components that form a plug in the blood vessel wall that stops bleeding. Platelets also produce a variety of substances that stimulate the production of a blood clot. One of the most common causes of increased bleeding risk is exposure tononsteroidal anti-inflammatory drugs (NSAIDs). The prototype for these drugs is aspirin, which inhibits the production of thromboxane. NSAIDs (for example Ibuprofen) inhibit the activation ofplatelets, and thereby increase the risk of bleeding. The effect of aspirin is irreversible; therefore, the inhibitory effect of aspirin is present until the platelets have been replaced (about ten days). Other NSAIDs, such as "ibuprofen" (Motrin) and related drugs, are reversible and therefore, the effect on platelets is not as long-lived.[citation needed]
There are several named coagulation factors that interact in a complex way to form blood clots, as discussed in the article oncoagulation. Deficiencies of coagulation factors are associated with clinical bleeding. For instance, deficiency of Factor VIII causes classichemophilia A while deficiencies of Factor IX cause "Christmas disease"(hemophilia B). Antibodies to Factor VIII can also inactivate the Factor VII and precipitate bleeding that is very difficult to control. This is a rare condition that is most likely to occur in older patients and in those withautoimmune diseases. Another common bleeding disorder isVon Willebrand disease. It is caused by a deficiency or abnormal function of the "Von Willebrand" factor, which is involved in platelet activation. Deficiencies in other factors, such as factor XIII or factor VII are occasionally seen, but may not be associated with severe bleeding and are not as commonly diagnosed.
In addition to NSAID-related bleeding, another common cause of bleeding is that related to the medication,warfarin ("Coumadin" and others). This medication needs to be closely monitored as the bleeding risk can be markedly increased by interactions with other medications. Warfarin acts by inhibiting the production ofVitamin K in the gut. Vitamin K is required for the production of the clotting factors, II, VII, IX, and X in the liver. One of the most common causes of warfarin-related bleeding is taking antibiotics. The gut bacteria make vitamin K and are killed by antibiotics. This decreases vitamin K levels and therefore the production of these clotting factors.
Deficiencies of platelet function may require platelet transfusion while deficiencies of clotting factors may require transfusion of eitherfresh frozen plasma or specific clotting factors, such asFactor VIII for patients with hemophilia.
Class I Hemorrhage involves up to 15% of blood volume. There is typically no change in vital signs andfluid resuscitation is not usually necessary.
Class II Hemorrhage involves 15–30% of total blood volume. A patient is oftentachycardic (rapid heart beat) with a reduction in the difference between thesystolic anddiastolic blood pressures. The body attempts to compensate withperipheral vasoconstriction. Skin may start to look pale and be cool to the touch. The patient may exhibit slight changes in behavior. Volume resuscitation with crystalloids (Saline solution orLactated Ringer's solution) is all that is typically required.Blood transfusion is not usually required.
Class III Hemorrhage involves loss of 30–40% of circulating blood volume. The patient'sblood pressure drops, theheart rate increases, peripheral hypoperfusion (shock) with diminishedcapillary refill occurs, and the mental status worsens. Fluid resuscitation with crystalloid and blood transfusion are usually necessary.
Class IV Hemorrhage involves loss of >40% of circulating blood volume. The limit of the body's compensation is reached and aggressive resuscitation is required to prevent death.
This system is basically the same as used in the staging ofhypovolemic shock.
Individuals in excellent physical andcardiovascular shape may have more effective compensatory mechanisms before experiencing cardiovascular collapse. These patients may look deceptively stable, with minimal derangements in vital signs, while having poor peripheral perfusion. Elderly patients or those with chronic medical conditions may have less tolerance to blood loss, less ability to compensate, and may take medications such as betablockers that can potentially blunt the cardiovascular response. Care must be taken in the assessment.[citation needed]
Although there is no universally accepted definition of massive hemorrhage, the following can be used to identify the condition: "(i) blood loss exceeding circulating blood volume within a 24-hour period, (ii) blood loss of 50% of circulating blood volume within a 3-hour period, (iii) blood loss exceeding 150 ml/min, or (iv) blood loss that necessitates plasma and platelet transfusion."[9]
Acute bleeding from an injury to the skin is often treated by the application of direct pressure.[11] For severely injured patients,tourniquets are helpful in preventing complications ofshock.[12]Anticoagulant medications may need to be discontinued and possibly reversed in patients with clinically significant bleeding.[13] Patients that have lost excessive amounts of blood may require ablood transfusion.[14]
The use ofcyanoacrylate glue to prevent bleeding and seal battle wounds was designed and first used in theVietnam War.[15] Skin glue, a medical version of "super glue", is sometimes used instead of using traditional stitches used for small wounds that need to be closed at the skin level.[16]
The word "Haemorrhage" (orhæmorrhage; using theæ ligature) comes from Latin haemorrhagia, from Ancient Greek αἱμορραγία (haimorrhagía, "a violent bleeding"), from αἱμορραγής (haimorrhagḗs, "bleeding violently"), from αἷμα (haîma, "blood") + -ραγία (-ragía), from ῥηγνύναι (rhēgnúnai, "to break, burst").[17]
^Roth, Elliot J. (2011)."Hemorrhage".Encyclopedia of Clinical Neuropsychology. Springer. pp. 1234–5.doi:10.1007/978-0-387-79948-3_2178.ISBN978-0-387-79947-6.Hemorrhage is active bleeding, in which blood escapes from the blood vessels, either into the internal organs and tissues or outside of the body.
^Manning JE (2003). "Fluid and Blood Resuscitation". In Tintinalli JE, Kelen GD, Stapczynski JS (eds.).Emergency Medicine: A Comprehensive Study Guide (6th ed.). McGraw Hill. p. 227.ISBN978-0-07-150091-3.
^Scerbo, MH; Holcomb, JB; Taub, E; Gates, K; Love, JD; Wade, CE; Cotton, BA (December 2017). "The Trauma Center Is Too Late: Major Limb Trauma Without a Pre-hospital Tourniquet Has Increased Death From Hemorrhagic Shock".J Trauma Acute Care Surg.83 (6):1165–1172.doi:10.1097/TA.0000000000001666.PMID29190257.S2CID19121937.
